In many construction projects, holes are drilled in structural concrete ceilings and other overhead structures, hereinafter referred to as ceilings, for subsequent installation of fasteners for plumbing, electrical and communications wiring, false ceilings, and sprinkler systems. In other cases these fasteners are applied, without pre-drilling of a hole, by an impact tool which uses an explosive charge to propel the fastener into the ceiling. Typically, these operations are conducted while other construction work is being carried out at the work site.
The conventional manner of conducting these operations is to use a hand-held power or impact tool while the operator is standing on a ladder or a scaffold erected at the work site. Scaffolds are often quite large and can obstruct other construction work at the site while in use. Often, the scaffold must first be assembled at one location and after the hole is drilled or the fastener is installed in the ceiling, the operator must dismount the scaffold to move it to another location, and at times, the scaffold must be disassembled and then reassembled at the next location. Assembly and disassembly of the scaffold is very time-consuming and awkward at busy construction sites. Even if the scaffold is equipped with rollers or castors, the scaffold is quite cumbersome and a large path must be cleared in order to allow the scaffold to be moved from one location to another. While it is possible for a single operator to move the scaffold on rollers or castors to another location, this step is very time-consuming and inconvenient.
Alternatively the operator can use a ladder to reach the ceiling. The operation however is still very time-consuming even though the ladder is more readily assembled and moved than is the scaffold. The operator must put the ladder in position and then climb the ladder with the power or impact tool to drill the hole or install the fastener. The operator must then dismount the ladder with the tool, bend over to put the tool on the floor, and move the ladder to the next position. He must then return to the previous position to pick up the power or impact tool and repeat the procedure.
It will be -Appreciated by those skilled in the art, that when the holes or fasteners are to be positioned, on the average, four feet apart, the scaffold or ladder must be moved many times during the project. For each hole or fastener, there is expended much non-productive time for both the operator and other workers in the vicinity.
Furthermore, the drilling of holes in structural concrete ceilings by means of a hand-held drill from a swaying scaffold or ladder is awkward and very hard work. The operator is exposed to noise, dust, and vibrations during the drilling operation and, all the while, he must hold his arms above his head. This type of work is very tiring and cannot be carried out for long periods. This problem is compounded in the use of the impact tool because more force is required to propel the fastener into the ceiling. If the operator loses his balance on the swaying ladder or scaffold during the operation, the tool may fall to the ground injuring workers in the vicinity or worse, the operator may fall off the ladder or scaffold.
Canadian Patent Number 1,218,543 (Klingstedt et al) describes a bore frame, upon which a power drill can be mounted, to enable the drilling of holes in ceilings directly from the floor below. The bore frame has an adjustable tubular body and a tool holder which is connected by a wire over a guide pulley to a handle hingedly attached to the outer tube of the tubular body. In this embodiment of the Klingstedt device, the tool holder moves relative to the tubular body of the bore frame.
In operation of the power drill mounted on the Klingstedt bore frame, the operator must stabilize the tubular body with one hand while operating the handle with the other hand. When the handle is depressed, the chain is guided over the pulley to move the tool holder and the drill upwards to the ceiling. A switch is located on the tubular body for operation of the power drill. The operator must activate this switch with the same hand that is used to stabilize the tubular body. Simultaneously, the handle must be depressed gradually with the other hand to control the feed of the drill.
It will be understood by those skilled in the art that, as the drilling operation continues with one hand holding the tubular body and the other hand depressing the handle, the operator's body must bend sideways into a very awkward position. This position of the body could be very painful for many people with back problems, especially after repeating this movement many times in one day. In fact, it may be impossible for some people to move their body in this position particularly while operating the power drill. The operator may even lose his balance in operation of this device. The safety of the operator and other workers at the site could be at risk.
As the drilling operation continues the operator's hands are further distanced from each other and the body position becomes very awkward making it easy for the operator to cause the drill to move sideways unintentionally. Moreover, the hand that is used to stabilize the frame is not totally dedicated to the stability of the frame as it must also be used to activate the switch. This could seriously affect the safety of the operator and other workers at the construction site. The device of the Klingstedt patent is also equipped with a level on the tubular body, presumably to prevent this unintentional movement of the drill. As discussed previously however it could be very difficult for the operator to view the level while simultaneously looking at the ceiling to monitor the operation.
In another embodiment of the bore frame described in Canadian Patent Number 1,218,543, the tool holder is rigidly attached to the tubular body which is movable in a sleeve at the base of the tubular body. The operating handle is hingedly attached to both the base sleeve and the tubular body. Again, the operator must stabilize the tubular body with one hand while operating the handle with the other hand. When the handle is depressed the tubular body moves upward relative to the base sleeve. The drill is operated by pulling a chain with the same hand that is also stabilizing the tubular body to cause a yoke to activate the switch on the drill. The operator must use one hand to push the operating handle in a downwards direction and the other hand to pull a chain causing operation of the drill. Once again the operator is forced into a very awkward position as he bends sideways to operate the handle. The problems discussed earlier are even further compounded in this embodiment because the tubular body is moved upward by depressing the handle. The hand that is stabilizing the tubular body and operating the switch also rises with the tubular body as the other hand pushes the handle downward. Stability of the bore frame and the safety of the operator are very serious concerns.
The present invention overcomes the problems of the prior art by enabling the drilling of holes or the installation of fasteners by an impact tool in a ceiling directly by an operator standing on the floor below the ceiling. The extendable arm of the present invention is convenient for the operator as it can be moved from one location to another by a single operator. The operator is able to stabilize the apparatus with both hands while operating the drill. The operation is more accurate and safer for both the operator and other workers at the construction site.